Sterilization testing device

ABSTRACT

The invention relates to a sterilization testing device comprised of a housing with a test chamber, an indicator placed therein, and with a supply for supplying the sterilization medium. According to the invention, the sterilization testing device consists of at least two housing parts that are matched to one another. A supply channel is made inside the housing part and serves to supply the sterilization medium. The supply channel is configured in such a manner that it forms the base body of the test chamber. The test chamber accommodates the indicator that indicates the completion of the sterilization process. Alternatively to this solution, the invention provides a variant, which is very effective with regard to manufacturing and which permits a quantitative statement regarding the sterilization. Webs are formed inside the housing in the at least partially meandering and/or spiral configuration of the supply channel. These webs, together with, at least in part, the lateral part(s) of the housing parts form a portion of the supply channel. A supply channel formed in this manner accommodates the indicator.

The invention relates to a sterilization testing apparatus comprising ahousing with a testing chamber, an indicator placed therein, and asupply line for supplying the sterilizing medium.

Sterilization apparatuses are used to be able to decide with adequatecertainty after a sterilization whether the sterilization procedure wassuccessful.

Preferably a gaseous or vaporous medium is provided as the sterilizationmedium, e.g., steam, ethylene oxide, or formaldehyde. In particular withso-called steam sterilizers like those employed in hospitals, long tubesand medical tools and equipment must be able to be sterilized with aprobability approaching certainty. In the case of steam sterilizers, asa rule the sterilizer is evacuated prior to supplying the e.g. normally121° C. or 134° C. hot saturated steam. The effect of this is that thesterilization agent travels unimpeded through the residual gasesremaining in the sterilization item to the locations to be sterilized.For this, it is necessary that the testing chamber with the indicator isconnected to the atmosphere of the steam sterilizer only via a supplyline that is very long relative to its cross-section.

The coupling of the supply line to the testing chamber represents a weakpoint in the sterilization testing apparatus.

Thus, in accordance with DE 43 19 397 C1 it is established that giventhe aforesaid conditions damage to the supply line is conceivable. Thedamage can begin at the connection or coupling between supply line andtesting chamber. Even minor leaks can be sufficient for the path of theambient sterilization atmosphere to be shortened, while circumventingthe longer path through the supply line, so that the indicator locatedin the testing chamber incorrectly indicates complete sterilizationand/or adequate sterilization conditions.

The connection from the supply line to the testing chamber is alsofrequently found to be the weak point of the testing system because thesupply line hangs loose on the testing chamber and/or its container andthis coupling point is mechanically stressed when the testing body isused.

In accordance with DE 43 19 397 C1, for these reasons the supply lineembodied as a tube is replaced by a stopper made of porous material thatmakes it more difficult for the sterilization agent to flow into thetesting chamber like a labyrinth seal. When used frequently, thissolution has the disadvantage that the stopper acts not only like alabyrinth but also like a barrier to the sterilization agent.

With DE 197 24 158 A1, the described disadvantages are intended to berectified in that a sterilization testing apparatus is created with asupply means embodied as a long extended tube, whereby the supply lineis closely packed—mechanically immobile—on the container. However, thedisadvantage of this solution is that the supply line still is notprotected from damage, even if it is practically securely connected tothe container of the testing chamber and thus the connecting parts areno longer subject to mechanical stress. In addition, producing thisproposed solution is very complex.

The known sterilization testing apparatus have an additionaldisadvantage.

The indicator must be placed in the sterilizer by the operator prior tothe sterilization procedure and must be removed again for documentationpurposes after the sterilization. As a rule, the testing chamber isclosed by a cover that can be inserted or screwed on. These coversgenerally have a seal that is intended to prevent the short-circuit ofthe surrounding sterilization agent and testing chamber and must betested regularly and replaced if necessary. If the cover and/or the sealhas a leak, it is not possible to check whether the indicator isdisplaying successful sterilization due to the leak in the cover or theseal or due to correct sterilization. Likewise, it is possible that theindicator is pinched between the testing chamber wall and the cover whenthe cover is screwed or placed on.

With sterilization apparatus, it is necessary that an indicator isconnected to the atmosphere of the sterilizer only through a supply linethat is very long relative to its cross-section. Using the interactionof the sterilization medium, with a supply line that is very longrelative to its cross-section, with the indicator it can be demonstratedin models that even hollow spaces and tubes or porous materials areacted upon or penetrated with the sterilization medium.

In DE 102 13 066 A1, a solution for such a sterilization apparatus isproposed in which a hollow diffusion space is formed from two thin films(wall elements) by a protuberance, at least in one of the films, and thesecond film closes off this hollow diffusion space from the outside sothat it is sterilization medium-tight. An indicator is arranged in thehollow diffusion space.

These solutions provide a number of advantages over the existingsystems. For one thing, there is no coupling point between testingchamber and supply line, and for another thing it is designed as adisposable item, which greatly simplifies handling of the system.

The disadvantage of this solution is that the supply line tube, in thiscase called the hollow diffusion space, is subjected to mechanicalinfluences in the sterilization chamber with no protection. The effectof even such a very slight porosity of the hollow diffusion space isthat the sterilization medium travels to the indicator, havingcircumvented the complete path via the entire diffusion segment.

Another disadvantage is that the indicator cannot be removed from thetesting body. Although DE 102 13 066 A1 does describe that the completesystem is to be archived, given the dimensions as suggested inprEN13060: 2002 and/or in EN 867-5 4.5, the testing system is severalmillimeters thick, so that the testing system is not suitable forcomplete documentation.

It is therefore the object of the invention to create a sterilizationtesting apparatus whose supply line to the testing chamber has thedimensions required for conventional steam sterilization without havingthe weak points at the coupling point and that at the same time isprotected against mechanical effects. In addition to its greatcompactness, the sterilization testing apparatus should make it possibleto open and close the sterilization testing apparatus with no problemfor the purpose of removing the indicator. Furthermore, it should bevery simple to produce in terms of production engineering, it shouldmake it possible to evaluate the performance of a sterilizer in a simplemanner, and it should ensure recoverability for disposable items.

This object is inventively attained in that the sterilization testingapparatus comprises at least two housing parts (3) and (5) that arematched to one another, whereby worked into the housing part (3) is asupply channel (4) that supplies the sterilization medium.

The supply channel (4) is arranged such that it forms the base body ofthe testing chamber (1). The testing chamber (1) receives the indicator(2) that indicates the conclusion of the sterilization procedure.

The supply channel (4) has an opening (7) and (7′) both to the testingchamber (1) and to the outside. Thus the sterilization medium can beconducted in from outside via the supply channel (4) that is open there.The supply channel (4) likewise opens into the testing chamber (1).Connectors and coupling parts are not required.

The supply channel (4) worked into the housing part (3) has any desiredcross-section. This can preferably be rectangular or square. Since thesupply channel (4) has a very thin cross-section while simultaneouslyhaving substantial length relative thereto, it particularly makes senseto embody such a supply channel (4) in a meandering or spiral shape.

Fundamentally the housing parts can be designed selectively such thatthey provide the option to be opened and closed both prior to and afterthe sterilization procedure in order to provide access to the indicator(2) or the housing parts (3) and (5) are securely joined to one another.The latter variant represents a particularly advantageous embodiment ofthe invention. In this case the indicator (2) is already placed in thetesting chamber (1) during production of the sterilization testingapparatus so that it is not necessary to open the testing apparatusuntil after the sterilization procedure has concluded to remove theindicator (2).

In order to be able to make it possible to access the testing chamber(1) for removing the indicator (2), provided in the housing part (3) or(5) is an opening (6) that is closed by means of a closure (12) forthose cases in which the housing parts (3) and (5) are securely joinedto one another.

Such a closure (12) can be embodied in a particularly advantageousmanner as a single use opening. This always makes sense when the twohousing parts (3) and (5) are securely joined to one another and thusare likewise provided for single-instance use.

However, the invention also permits additional options to be able tocheck the indicator (2) for its reaction during single-instance use ormultiple use.

Thus, in one additional embodiment of the sterilization testingapparatus, the housing parts (3) and (5) are detachably joined to oneanother. In such an embodiment, the housing parts (3) and (5) can beopened and closed in a simple manner for placing and/or for removing theindicator (2). Such an embodiment can be manufactured from metal, forinstance. A seal (10) should then be placed in an advantageous mannerbetween the housing parts (3) and (5). It has been demonstrated that asealing mat that is contained in the housing part (5) is particularlysuitable for this. Such a sealing mat could comprise for instancesilicon material.

In the inventive solution of housing parts (3) and (5) joined securelyto one another, it is also possible to do without an opening (6) with aclosure (12) in that the sterilization testing apparatus is opened, andthus the indicator (2) can be removed, by breaking the housing parts (3)and (5) at the predetermined breaking line (13).

Likewise for housing parts (3) and (5) that are securely joined to oneanother it is inventively provided that the housing parts (3) and (5)are produced from a transparent material in order to be able to view theindicator (2) and/or determine its reaction without opening theapparatus or breaking it on a predetermined breaking line (13).

Another embodiment of the sterilization testing apparatus provides thatit comprises more than two housing parts (3) and (5) that are matched toone another. This is a so-called multilayer sterilization apparatus.This embodiment provides the option of producing sterilization testapparatus that are shorter in width and length than in height in termsof their physical dimensions.

In this case, the housing part (3″) contains the supply channel (4) withan opening (7) that produces a connection to the outside. The housingpart (3′) also contains a supply channel (4) that is provided with anopening (7′) that enables a connection to the testing chamber (1) withan indicator (2) placed therein. Both housing parts (3′) and (3″) arethemselves joined to one another by an opening (11).

In the multilayer embodiments, a meandering or spiral (shape) alsoinventively makes sense in order to be able to house, if needed, thenecessary length of the supply channel (4) in particularly smallhousings (3) and (5) of the sterilization testing apparatus. For themultilayer embodiment, the inventive solutions listed above can be used;these have already been provided and described for single-layer housingparts (3) and (5) that are joined securely to one another.

Advantageously, the housing parts (3) and (5) comprise plastic, wherebyeach of the housing parts can also comprise different plastic materials.This always makes sense when a transparent plastic material is used sothat the indicator (2) can be visible.

It has been demonstrated that the housing parts (3) and (5) made of aheat-resistant plastic that is suitable for an injection molding processare particularly favorable materials for producing the inventivesterilization testing apparatus.

Alternatively to this solution in which for removing the indicatorprovided in the housing part (3) or (5) is an opening that must beclosed with a single-use closure, in accordance with the invention avariant that is very effective in terms of production engineering isproposed that makes possible a quantitative statement about thesterilization. This variant of the sterilization testing apparatus thuspermits not only a statement about whether the sterilization procedurehas been completed, but furthermore even provides information about theperformance of the sterilizer.

This is inventively attained in that the supply channel (4) thatsupplies the sterilization medium can be worked into the housing part(3) or into the housing part (5) or into both. Using an at leastpartially meandering and/or spiral-shaped arrangement of the supplychannel, ridges form in the interior of the housing, and these ridges atleast partially along with the side part(s) of the housing parts (3)and/or (5) form a part of the supply channel (4). A supply channel (4)formed in this manner receives the indicator (2).

The invention selectively also provides that the supply channel can bearranged such that using this arrangement or at least a part of a sidepart of the housing part(s) (3) and/or (5) a testing chamber (1) iscreated in which an indicator (2) can be placed.

The supply channel (4) worked into the housing part (3) and/or (5) hasany desired cross-section. Preferably it can be embodied rectangular orsquare.

A very compact construction is obtained by working the supply channelinto the housing part. The supply channel is situated protected in theinterior of the housing and is optimally protected against externaldamage.

In accordance with one preferred embodiment, the supply channel (4) hasa length that is so long relative to its cross-section that under normalsterilization conditions the supply channel (4) cannot be completelydeaerated.

In this case, it makes sense to place into the complete supply channelone or a plurality of indicators that indicate the precise segment up towhich the sterilization medium has penetrated. The subordinate claimspropose such advantageous embodiments in which the indicator (2) isdistributed selectively over the entire length of the supply channel ora plurality of indicators (2) is distributed over the length of thesupply channel (4).

This embodiment is suitable for instance for periodic tests of thesterilizer, since in contrast to conventional sterilization testingapparatus it provides a quantitative statement about the maximum segmentfor which sterilization is attainable for instance for a tube withuniform diameter and it is possible to detect trends in the performanceof the sterilizer early on. For this, it makes sense to apply a type ofscale to the housing in order to be able to read and document the valueswith certainty. In this case, the housing should be produced from atransparent material so that the result can be read directly. In thisaforesaid embodiment it also makes sense that the sterilization testingapparatus comprises more than 2 housing parts (3) and (5) that arematched to one another. Thus, this is a multilayer sterilization testingapparatus that is shorter in width and length than in height in terms ofits physical dimensions.

A sterilization testing apparatus employed for disposable use isinventively provided with a machine-readable continuous code, since inthis manner clear recoverability of the testing systems is provided upto the production process for the testing apparatus.

Advantageously, the housing parts (3) and (5) likewise comprise plastic,whereby each of the housing parts can also comprise different plasticmaterials. This always makes sense when a transparent plastic materialis used so that the indicator (2) is visible through the housing parts(3) and/or (5). It has been demonstrated that the housing parts (3) and(5) made of a heat-resistant plastic that is suitable for an injectionmolding process are particularly favorable materials for producing theinventive sterilization testing apparatus.

Selectively the housing parts can also be designed such that they offerthe option of opening and closing both before and after thesterilization procedure so that the indicator (2) can be accessed or thehousing parts (3) and (5) are securely joined to one another.

In the latter case, the ridge(s) (9) and the housing parts (3) and (5)the supply channel (4) are embodied such that they close sterilizationmedia-tight to the outside and to themselves.

In the embodiment in which the housing parts are securely joined to oneanother, selectively worked into the housing part (3) or (5) is a tearstrip (14) that, by tearing it, permits the housing part (3) or (5) tobe opened and the indicator (2) to be removed.

Another particularly preferred embodiment is comprised for the case inwhich the housing part (3) or (5) that does not contain the ridge(s) (9)represents a film (16). Such a solution represents a particularlycost-effective variant of the invention.

The particular advantage of the inventive solution is comprised inproducing a very cost-effective sterilization testing apparatus, sincethe latter can be produced in very high numbers. There is thepossibility of designing the invention such that it can be employed forsingle use or multiple use.

One particular advantage is attained in the utilization of thesterilization testing apparatus in single use, however. An exceptionallycompact apparatus results that offers particular protection fromexternal influences. Since in the field of sterilization a great deal ofvalue must be placed on certainty and in particular there must be as fewsources of errors as possible for personnel, this compact solution is apreferred embodiment. The greatest possible certainty is attained withthe compact sterilization testing apparatus in that hospital personnelcannot have any effect on the testing apparatus prior to or after thesterilization procedure by opening and closing the apparatus.

The personnel need only place the sterilization testing apparatus intothe sterilization machines and, after the sterilization cycle, eitheractuate the single-use opening for the purpose of removing the indicatoror read the results of the sterilization from the indicator through thetransparent half of the housing.

The inventive solution is illustrated using drawings in FIG. 1 throughFIG. 15 to provide a more detailed explanation.

(FIG. 1) A top view of the housing part (3)/(5) without correspondinghousing part (5)/(3) with spiral-shaped or meandering supply channel(4), embodied testing chamber (1) with indicator (2) placed therein.

(FIG. 2) illustrates a housing part (3) or (5) into one of which aspiral-shaped supply channel (4) is worked and into one of which ameandering supply channel (4) is worked and at least one ridge (9) isformed by these supply channels (4). It is also very easy to see how thesupply channel (4) is formed by the housing side parts (15) and theridge(s) 9.

(FIG. 3) illustrates a sectional illustration of a sterilization testingapparatus with a spiral-shaped supply channel (4) worked into thehousing (3) that is securely joined to a housing part (5) and thehousing part (5) has an opening (6) that is closed by a closure (12).The indicator (2) is placed directly into the supply channel (4).

(FIG. 4) is an exploded illustration of a sterilization testingapparatus with a spiral-shaped supply channel (4) in the housing part(3) or (5). The housing part (5) or (3) has an opening (6) that isclosed with a closure (12). The indicator (2) in the testing chamber (1)is accessed by opening the closure (12).

(FIG. 5) illustrates (FIG. 4) as assembled.

(FIG. 6) illustrates a multilayer sterilization apparatus.

(FIG. 7) is a top view of the housing part 3′ with opening (11).

(FIG. 8) is a variant of a multiuse sterilization testing apparatus inwhich unintentional opening of the housing parts (3) and (5) isprevented by clamps (8).

(FIG. 9) is a variant of a multiuse sterilization testing apparatus,whereby the housing part (3) and the seal (10) are inserted into thehousing part (5).

(FIG. 10) is a single-use sterilization testing apparatus in which thehousing parts (3) and (5) are broken on the predetermined breaking line(13) in order to remove the indicator (2).

(FIG. 11) illustrates a sterilization testing apparatus in which it isschematically illustrated that a supply channel (4) is worked in that isvery long compared to its cross-section and that under normalsterilization conditions cannot be completely deaerated. In this casethe indicator (2) is placed over the complete length of the supplychannel (4) in order to check the extent to which the sterilizationmedium has penetrated in the supply channel (4).

(FIG. 12) illustrates a partially meandering and spiral-shapedembodiment of the supply channel (4). The indicator (2) in this case isplaced in the complete supply channel (4).

(FIG. 13) is an exploded drawing illustrating how the housing part (5)or (3) can be opened using a tear strip (14) in order to be able toremove the indicator (2).

(FIG. 14) is an exploded drawing of a sterilization testing apparatus inwhich a plurality of indicators (2) is placed in the housing part (3) or(5). The individual indicators (14) [sic] can be removed by opening thetear strips (14).

(FIG. 15) illustrates one preferred embodiment in which the supplychannel (4) is worked into the housing part (3) or (5) and the housingpart (5) or (3) is sealed with a transparent film (16).

In these figures,

-   (1) Test chamber-   (2) Indicator-   (3) Lower housing part-   (3′) Housing part in multilayer embodiment-   (3″) Housing part in multilayer embodiment-   (4) Supply channel-   (5) Upper housing part-   (6) Opening in the housing part (3), (5)-   (7) Opening on supply channel (4)-   (7′) Opening on supply channel (4) to testing chamber (1)-   (8) Clamps-   (9) Ridge(s)-   (10) Seal-   (11) Opening between (3′) and (3″)-   (12) Closure to (6)-   (13) Predetermined breaking line-   (14) Tear strip-   (15) Housing side part-   (16) Film

The invention is explained in the following using several exemplaryembodiments.

One preferred embodiment is comprised in that the housing parts (3) and(5) are made of a heat-resistant and mechanically resistant plasticmaterial and are produced in an injection molding process. The housingpart (5) has an opening (6) that is closed with a single-use closure(12). The single-use closure (12) comprises a mechanically resistant andheat-resistant film that during production is stamped gas-tight and thuscloses off access to the testing chamber (1).

The housing parts (3) and (5) are permanently joined to one another inthe production process by ultrasound welding after the indicator (2) hasbeen placed in the testing chamber (1).

After sterilization has been performed the film is torn off to open thesterilization testing apparatus in order to be able to remove theindicator (2) from the testing chamber (1).

Another preferred embodiment of the invention provides that the supplychannel (4) in the housing part (3) or (5) is arranged such that thesupply channel (4) opens into a testing chamber (1) after a certainlength. Thereafter the supply channel continues and opens into the nexttesting chamber. This system of sequential supply channels and testingchambers should be designed to be long enough that under normalsterilization conditions it cannot be completely deaerated. The housingpart (3) or (5) can be opened using the tear strips in order to accessthe indicators. Thus it is possible to determine the length to which thesupply channel could be deaerated.

In that the preferred embodiment concerns a disposable item, it has beendemonstrated that it is advantageous to be able to uniquely identify thedisposable item using a serial number. It has also proved advantageousto encipher the serial number as a bar code.

In another advantageous embodiment of the invention, the supply channel(4) is worked into the housing (3) or (5). The supply channel opens intoa testing chamber in which an indicator has been placed. The housingpart (3) or (5) is sealed with a transparent film so that reaction ofthe indicator can be checked through the film and the indicator isaccessible by removing the film.

1-24. (canceled)
 25. Sterilization testing apparatus comprising ahousing including a testing chamber, a supply line for supplying asterilizing medium to the testing chamber, at least one indicatorlocated in at least the testing chamber for indicating completion ofsterilization, the housing being comprised of an assembly of at leasttwo superimposed parts, the supply line being comprised of a channelformed in at least one of the housing parts, the channel having anopening at one end thereof communicating with the testing chamber and anopening at the other end thereof for communicating with a source of thesterilizing medium outside the housing.
 26. Sterilization testingapparatus according to claim 25, wherein the supply line and/or thetesting chamber is comprised of at least one ridge formed on interiorsurfaces of at least one of the housing parts and side walls of at leastone of the housing parts.
 27. Sterilization testing apparatus accordingto claim 25, wherein length of the supply line relative to cross-sectionthereof is sufficiently great to prevent complete deaeration of thesupply line during sterilization.
 28. Sterilization testing apparatusaccording to claim 25, wherein the indicator is a single indicator whichextends over the entire length of the supply channel.
 29. Sterilizationapparatus according to claim 25, wherein a plurality of the indicatorsand distributed over the entire length of the supply channel. 30.Sterilization testing apparatus according to claim 25, wherein, apartfrom said opening communicating with a source of the sterilizationmedium, the housing is hermetically sealed.
 31. Sterilization testingapparatus according to claim 25, wherein the supply channel is of squareor rectangular cross-section.
 32. Sterilization testing apparatusaccording to claim 25, wherein the supply channel follows a spiral ormeandering path.
 33. Sterilization testing apparatus according to claim25, wherein the housing parts are fixedly secured together. 34.Sterilization testing apparatus according to claim 25, wherein the atleast one ridge is formed on only one of the housing parts. 35.Sterilization testing apparatus according to claim 25, wherein at leastone of the housing parts comprises a transparent material which makesthe indicator visible without opening the housing.
 36. Sterilizationtesting apparatus according to claim 31, further comprising a breakingline along which the housing parts are manually breakable to provideaccess to the indicator.
 37. Sterilization testing apparatus accordingto claim 31, further comprising a least one tear strip in the housingparts, tearing away of the tear strip providing access to the indicator.38. Sterilization testing apparatus according to claim 31, furthercomprising an opening in one of the housing parts for providing accessto the indicator and an openable closure for the opening. 39.Sterilization testing apparatus according to claim 25, wherein theclosure comprises a film suitable not adapted for re-closing theopening.
 40. Sterilization testing apparatus according to claim 25,further comprising a serial number applied to at least one of thehousing parts.
 41. Sterilization testing apparatus according to claim40, wherein the serial number comprises a bar code.
 42. Sterilizationtesting apparatus according to claim 25, further comprising a scaleapplied to at least one of the housing parts.
 43. Sterilization testingapparatus according to claim 25, wherein the housing is comprised of anassembly of at least three superposed parts and the channel is comprisedof at least two superposed sets of channels communicating with eachother.
 44. Sterilization testing apparatus according to claim 25,wherein the housing parts are detachable from each other and furthercomprising a seal between the housing parts.
 45. Sterilization testingapparatus according to claim 44, wherein the seal comprises a mat. 46.Sterilization testing apparatus according to claim 25, wherein housingparts comprise at least one heat-resistant plastic.
 47. Sterilizationtesting apparatus according to claim 25, wherein the housing partscomprise at least one injection molded heat-resistant plastic.